The present invention relates to improved tire inspection equipment, and more particular to equipment for inspecting used tires prior to retreading.
Various types of equipment and procedures are currently used to inspect new tires and used tires. Such inspections are preferably conducted to find hidden irregularities or defects prior to retreading used tire casings. Economic loss occurs from retreading a damaged tire casing and later scrapping the resulting retread tire. Even greater loss may occur from potential safety hazards associated with using a retread tire having a damaged tire casing.
Most modern tires used on trucks and automobiles have multiple steel cords integrally molded within the associated tire casing. Work hardening of the steel cords may occur from operating the associated tire with less than the recommended air pressure. This type of defect in a used tire casing is sometimes referred to as a xe2x80x9czipper.xe2x80x9d Catastrophic failure may occur from retreading a used tire casing with damaged steel cords. For example, a new tire or a retread tire, after mounting on a tire rim, is often over pressurized to set or seal the associated tire beads within the rim. During over pressurization, catastrophic failure may occur in the vicinity of the damaged steel cords. As a result of such potential hazards, most major fleet tire dealers require inspection of used tire casings prior to retreading.
Although substantial efforts have been made to minimize dust, debris and other contamination associated with retreading used tires, tire inspection equipment must operate in an environment which is less than ideal for modern electronic components. Also, tire inspection equipment is frequently subject to significant mechanical vibration during handling and rotation of used tire casings. Contamination of electronic components and/or damage to electrical wiring and electrical circuits may reduce the overall operating efficiency of some types of tire inspection equipment.
Examples of tire inspection equipment and techniques are shown in U.S. Pat. No. 4,936,138 entitled Method And Apparatus For Tire Inspection and U.S. Pat. No. 4,520,307 entitled High-Voltage Tire Testing Apparatus. For many years Oliver Rubber Company located at P.O. Drawer 1827, Athens, Ga. 30603-1827 has manufactured and sold Tuff-Scan(copyright) and Wide-Scan(copyright) ultrasonic tire casing inspection equipment.
In accordance with teachings of the present invention, substantially enhanced tire inspection equipment and methods are provided. One aspect of the present invention includes tire inspection equipment having a movable energy transmitter assembly and a movable energy receiver assembly to detect energy from the transmitter assembly passing through a tire casing. For some applications sonic or ultrasonic energy may be used to find hidden defects or irregularities in a used tire casing. For other applications electromagnetic energy or a combination of electromagnetic and sonic or ultrasonic energy may be used.
Other aspects of the present invention include providing mechanical and electrical systems to coordinate movement of an energy transmitter assembly and an energy receiver assembly relative to each other for inspection of a tire casing. The mechanical and electrical systems cooperate with each other to allow inspection of a wide variety of tire sizes and types.
Technical benefits of the present invention include the ability to scan both the sidewalls and tread of a tire casing. Portions of the electrical system are preferably contained in an electronic console or control console remotely located from other mechanical components of the tire inspection system. The portions of the mechanical system used to move the receiver assembly relative to the transmitter assembly is preferably spaced from the portions of the mechanical system which support and rotate the tire casing during an inspection cycle. As a result of incorporating teachings of the present invention the possibility of damage to electrical and/or mechanical components from vibration associated with handling and rotating a used tire casing are minimized. Also, placing portions of the electrical system in a remotely located console will protect the associated electronic components from any contamination present in the tire retreading facility.
Further technical benefits of the present invention include a mechanical system which requires only one stroke setting to adjust movement of the transmitter assembly and receiver assembly to accommodate a specific size and type of tire casing. Existing tire inspection systems may be modified by adding mechanical and electrical components incorporating teaching of the present invention. Alternatively, new tire inspection equipment may be built with mechanical and/or electrical systems incorporating teachings of the present invention.